Whenever a new roof is installed the roofing materials must be cut at various angles, especially during the construction of hip-type roofs and valleys, where two sections of roof join each other. Roofing substrates such as plywood are relatively easy to cut at different angles with saws and the like. Asphalt roofing shingles are also relatively easy to cut at various angles with snips, razor knives and the like. However, sheet metal is oftentimes used for roofing material because of its durability. These sheet metal panels normally include at least one rib, extending along the length thereof to add strength to the panel. Many of the sheet metal roofing panels are approximately 24 inches in width. Conventional metal cutting shears, jig saws, and Sawzalls have not provided a satisfactory method for insuring a clean, smooth accurate cut when used for cutting ribbed metal roofing panels.